Interference-preventer for use in wireless-telegraph systems.



v B. MILLER & Al-H. 00X. INTERFERENCE PREVENTBR FOR USE IN WIEELRQS TE LEGBAPH SYSTEM-S.

' APFLIOATION FILED NOV. 16, 1912 WITNESSES:

llVVE/VTORS ATTORNEY Patented Jan. 5, 1915.

"shaman erm ne PATENT THOMAS B. MILLER AND ALLEEN Hi COX, F EAT'ILE, WASHINGLON, AS lG'NDI-ZS OF-ONE- HALF TO SMITH CANNERY MAGHINES COMPANY, OF SEATTLE. 'WASHINGTON, A

CORPORATION,

INTERFERENCE-PREVENTER FOR USE weenie Specification of Ietters Patent.

IN WIRELESS- TELEGRAPH SYSTElVIS.

Patented Jan. 5, 1915.

Application filed November 1. 1912. Serial No. 731,803.

' To all whom it may concern. 7

' station whereby radiant 'Hertzian electrical waves representing intelligible signals, which emanate from. a desired particular one of several other different distant wireless telegraph stations that are generating and sending out such waves, exclusively may be perceived and interpreted by a telegraph operator; and the object of our invention is to provide a wireless telegraph station with a system of circuits and apparatus associated therewith that shall be adapted to be adjusted to receive and clearly make readable to an operator the weak elec-.

tric waves from a most distant station, or

from 'a station of smallest power which is sending slgnals representedby the weakest of electric waves, without lnterference' or interruption by, or a perception by the operater of,stronger'electric'al waves which at the same tnne may be emanatlng from a nearby or" more powerful station. This object we attain by electrical circuits and de vices connected therewith which are illustrated in the accompanying drawings,

Figure 1 is a diagrammatic representat1on of the essent al mechanism ofo'ur 1nvention as connected wlth the clrcuits of a ,re'ceiving apparatus of a wireless telegraph Station and Fig. 2 is a perspective View showing the most essential portions of suchmechanism and the relat ve posltions of their operative parts. 9 I

, Like reference numerals lndlcate like I parts throughout the drawings.

It ferring to Fig. .1 ofthe drawings,-3

is the primary winding of an air-core transformer 1, one end of which winding is con nected with a ground 5 while itsother end 6 may be connected with the antenna of a wireless'station. The secondary winding 7 of .the air-core transformer 4 formsa part ofan oscillating circuit, one of its terminals being connected with one terminal of a telephone 8 and with one terminal of a condenser9 while its other terminal is connected through a rectifying detector 10 with the other terminal of the condenser 9and with'the other terminal of the telephone 8.

Connected in parallel with the rectifying detectorlOis a circuit 11 which includes a circuit-breaking switch 12 and a pair ofmovably adjustable needles, 13 and 14 preferably of small steel wire highly polished, disposed and supported at a right angle with each other. The needle 13 is fastened in and projects in a horizontal direction from one end of an iron armature 15 which is mounted tooscillate on a shaft 16 that may turn in suitably supported bearings, not show-n. Beneath the other end of the armature 15 is an electro-magnet 30 which may be connected with a source of varying electric current, as with an electric battery 31 whose current is varied by a buzzer 32,

as shown in Fig.2, whose varying energy may serve, in a manner well known, to cause the armature 15 to vibrate or oscillate to movethe needle .13 up'and down; Upon thetop of the armatuilfi ismounted fiat resilient springsl't' and 18, as more clearly shownin Fig. 2, whose effective action may be'varied respectively by adjusting screws 19 and 20 which project through suitably supported lugs 21 and 22 respectively,

whereby the amplitude ofvibration of the armature 15 may be controlled. The needle 14 is attached to the upper end of a spiral spring 23 whose lower end is secured to the upper end of a lever 2 1, more clearly shown in Fig. 2, which lever'24 is secured to a flat flexible spring 25 that is supported by a bracket 26 whereby the needle 1-1 normally may be disposed in a vertical position to rest against the horizontal needle 13. In-

tegral with the bracket 26 is an upright pro-I jection 27 adapted to support an adjusting screw28 which may serve to adjust the po-.

sition of the lever 24: to cau'se the needle 14 to have a desired pressure againstthe needle 13"' as the needle .13 moves upwardly and downwardly inresponse to vibrations of the armature 15. In; operation the needles 1.3 and 14 are Well covered with a film of oil, of QSuitable quality, whereby there shall always be present a thin film of oil between the needles 13 and 1 1 at their points of contact with each other. Such film of oil maybe maintained by disposing on each or one of the needles 13 and 14 a little ball29 of fibrous material, as of cotton, well satu:

break through the film of oil that is presentbetween the needles .13 and lt'but-can not serve to short-circuit waves of alternating polarity which are not strong enough in.

electro-motive force to break throughtsuch film of oil and thus such weaker waves of alternating polarity are confined to a "path I out a "ecting the receiving telephone 8; but a weakened waves of alternating polarity leading through rectifying detector .10 wherethrough only waves of like polarity may find passageway; and since'wave'smf like polarity may not readily be transmitted tl'irough the condenser 9 they are forcedtO 25.

pass through the telephone 8 to cause it to make perceptibly audible sounds; while the waves of alternating polarity that'Tare sufiiciently strong to break through the film of oil between the needles l3 and 14 find passageway of little resistance around the rectifying detector 10 and theninay pass readilv-through the condenser 9 (which can offer little. or no resistance to waves of alternating polarity) instead of passing through the parallelpath within which is connected the telephone 8, and thus such strong waves of a nearby station maynot actuate the telephone 8'or other electrical translating device that might be likewise disposed in a circuit parallel with the condenser 9. Thus, in operation, strong waves of an alternating polarity of a nearby. station or of a distant but more powerful station, acting on the primary winding 3, may induce corresponding waves in the secondary winding 7 whereupon, with. the clrcuit-breakmg switch 12 closed, 'such corresponding waves may break through the film of oil between the needles 13 and 14 and find passageway through the circuit 11 and condenser 9 withemanating from a far distant station, not being able-to break through the film of oil between the needles13 and 14c, are subjected to the action of the rectifying detector 10 whereby only waves of a like polarity can pass ther'ethrough and such like waves areadapted to actuate the telephone 8 and are not adapted to be short circuitedtnrough g thecondenser 9, and therefore only the very weak wave signals of a desired one of sevis to cause the needle 13 to engage-with. the

needle 14 at different points successively whereby oil may be distributed always to form a film of oil between the two needles 13 and 14'since if the needle 13 be stationary thenminute electrical sparksimight cause -a carboniiation of the oil film and fresh -oil might'not find its way between'the points of engagement of the needles .13 and 14.

. lVehave shown only one form ofmechanism for controlling and adjusting the 1,80 needles'lS. and 14 and for constantly changing the position of the point o engagement between such needles but" various other 1 formsof mechanisms may be employed for -s uch'purpose without departing from the spirit of our invention.

What we claim is: 1. In th'ecreceiving system of a wireless 'telegra h station, the combination with an oscillating circuit, of'a pivoted magnet armature that is adapted by suitable electrdmagnetic means to be vibratedfametal electrodesecured to and projecting from said armature, a second metal electrode flexibly and adjustably mounted on suitable support-' ing means and adapted to be maintained in lubricated engagement with saidfirst named metal electrode, and means for maintaining a lubricated contact between said electrodes.

2. In areceiving apparatus for a'wireless telegraph station, the combination with an oscillating circuit that includes the secondary winding of a transformer, of a condenser, a rectifying detector, said condenser and said detector being connected in said oscillating circuit in series withsaid secondary winding, a translating device connected to said oscillatmg c1rcuit 1n parallel with sa1d condenser, and a shunt circuit connected to,

said oscillating circuit in parallel with said rectifying detector within whichshunt c1rcuit is included a resistance adapted to obstruct the passage of weak electric waves and to break down to pernnt the passage of strong electric waves.

In witness whereof, we hereunto subscribe our names this sixth day of November A. D., 1912.

THOMAS B. MILLER. ALLEN H. CQXL Witnesses F. C. MATHENY, ANNA HAsnms. 4 

